Deletes a Resource Manager instance (RMI) from the calling
    process.
    $FORGET_RMW always waits for the request to complete before
    returning to the caller. Other than this, it is identical to
    $FORGET_RM.
    Format
      SYS$FORGET_RMW  [efn] ,[flags] ,iosb ,[astadr] ,[astprm] ,rm_id
    C Prototype
      int sys$forget_rmw  (unsigned int efn, unsigned int
                          flags, struct _iosb *iosb, void
                          (*astadr)(__unknown_params), int astprm,
                          unsigned int rm_id);